GB784588A - Liquid fuel pumps for internal combustion engines - Google Patents

Abstract

784,588. Fuel injection pumps. C.A.V., Ltd. April 27, 1956 [May 13, 1955], No. 13853/55. Class 102(1). A fuel pump for internal combustion engines comprises a feed pump of the vane type, a fuel injection pump and a distributer for conveying fuel to each of the engine cylinders. Fuel is fed to the feed pump through a passage d, Fig. 1, the inlet and outlet ports of the pump being connected by a non-return valve e which limits the pressure generated. Fuel from the feed pump is conveyed through a passage m, past an annular groove n to a cavity o which contains a manually operated throttle p. Fuel passes along passage q to each in turn of the radial ports r in the distributer k, driven by a spindle 5 by motion from the engine, and thence along the bore s to the injection pump. During the inward movement of the plungers h, Fig. 2, of the injection pump the fuel is returned along the bore s to the single radial port t which feeds each of the engine cylinders in turn through passages u. Ports 3 in the distributer, similarly situated to radial ports r, convey fuel from the feed pump through a passage 2 to one side of the plunger w, Fig. 2. The pressure on the plunger w causes rotation of the cam j, against the springy, in the opposite direction to the rotation of the distributer k. When the plungers h encounter the cam lobes they impart a return movement to the cam so long as the passage 2 is open via ports 3. When the passage 2 is closed by the distributer the cam is locked hydraulically and the plungers perform their discharge movement. In a modified form to vary the instant at which the injection pump commences its action, Fig. 6 shows a cross-section of pump through ports 3 and channel 2. The ring 6 is angular movable by an arm 7, being operable by convenient means responsive to the engine speed. The fuel passes from the ports 3 to the radial port in the ring 6, through a groove surrounding the ring to the passage 2, to adjust the position of the cam as above. Alternatively instead of the ring 6 the ports 3 may have a chamfer at their trailing edge or the passage 2 a chamfer at its closing edge. In a modified form of Fig. 2 the spring y is on the left-hand side of the plunger and the right-hand side is connected continuously to the outlet side of the feed pump.